Speedy service is becoming the norm for many consumer products such as spectacles or optical lenses. To meet this demand, optical retail stores glaze and fit stock lenses into frames and advertise a 1-hour service. But the provision of multifocal or varifocal lenses presents difficulties. Approximately 80% of multifocal patients need a cylinder correction, and until recently there was no alternative to sending the prescription away to an optical laboratory for processing. A quick look at the existing options for speedy service in retail practice lens-making reveals the need for a high level of investment, either in cash or in experienced personnel, to be sure of quality lenses in the short time cycles desirable.
One solution has been for an optical practice to buy thin lens wafers and then assemble two such wafers together to provide a bi-focal lens according to the prescription. The wafers are bonded with UV sensitive adhesive and cured. Although relatively fast, this method ties the practice to a narrow range of lens forms obtained only from the original supplier. Another solution is to buy equipment which permits cast lenses to be made as they would be cast in a factory. However, curing such lenses takes at least three hours by water or overnight by air, and an inevitable proportion of rejects will leave some customers still disappointed. Moreover, the equipment requires an investment of about $70,000.
The most popular option at the present time, due to the sophisticated machine tools produced by several specialist optical engineering companies and a pool of skilled labor available from existing optical wholesalers, is to use traditional lens-surfacing machines and methods. However, a thousand square feet of floor space, ample power points, water supplies with good drainage and ideally three staff members makes for a major project. An investment of nearly $100,000 is called for by this option.